I see that it has a post on it. I wonder if they use that kind of Technology back that far. That may be a good place to start your research finding out when they started using pins
Is the metal silver or gold ?
It doesn't look like either.
Can you clean it up some ?
Any idea of what the false tooth is made of ?
Porcelain or bone ?
I'm guessing a relatively modern find because of the post on the tooth which should be surgical grade stainless steel.
I doubt Doc Holiday would be performing implants or root canals back in his time of primitive dentistry. http://www.biography.com/people/doc-holliday-9342122#early-years
I agree with Relic Lover. That post could be a clue to the age. You may try something as simple as asking a dentist, instead of internet research. I bet a lot of them would know dental history.